<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>示例3</title>
</head>
<body>
    <script>
        // var b = 3;
        // var b = 4;
        // console.log(b)

        let a = 1;
        let a = 2;
        console.log(a)
    </script>
</body>
</html>